This unit is designed to be used in conjunction with the ST- 266 Radius 1 or ST-263 Radius 3 Level Crossing to convert them to a double track crossing. Setrack Level Crossings can be positioned virtually anywhere on your layout. There are four radii available in curved crossings, plus the straight crossing and add on unit . These simply clip together so that you can cross up to four tracks on a curve and any number of tracks on the straight. They are supplied with traditional gates as standard, LK-51 modern barriers can be substituted if required.